The present invention relates to tunnel driving apparatus and, more particularly, to cutting appliances for detaching material from a tunnel working face.
It is well known to use a drive shield to create an underground excavation such as a gallery or adit referred to for convenience hereinafter simply as a tunnel. A variety of different types of drive shield can be utilized and in order to detach material from a working face of the tunnel likewise various cutting appliances are available. One such appliance is the so-called partial cut machine which has a swinging arm or jib which can be swivelled all over the face and carries a rotary cutter head at its free end. Where a tunnel is driven in loose soil or collapsible or frangible material which is essentially unstable, it is known further to support the work face with the aid of a thixotropic fluid introduced into a chamber open to the face but closed off from the rear of the tunnel with a bulkhead. The cutting appliance still serves to detach material from the work face but now a conduit or pipe laid along the outside of the cutting arm withdraws the debris material with some of the supportive fluid by suction. German patent specifications 2431512 and 2907768 describe apparatus of this type. In these known constructions, the drive for the cutter head is disposed at the rear side of the bulkhead. Getting and loading machines, however, are known in which the drive means for a cutter head is mounted inside the swinging arm carrying the head-see, for example, German patent specifications 1921093 and 2256917.
A general object of the present invention is to provide an improved cutting appliance for tunnel driving operations.